Dragline boom

ABSTRACT

A dragline boom with a pulley around which a hoisting rope passes carried on its free end, mounted with the aid of bearings on a bush installed with the possibility of rotation by means of a pin on a cross-piece secured on the free end of the boom. The pin is arranged perpendicular to the cross-piece, and the longitudinal axis of this pin is offset upwardly relative to the longitudinal axis of the bush.

[ 51 Aug. 15,1972

United States Patent Marichev et al.

[56] References Cited UNITED STATES PATENTS DRAGLINE BOOM 00000 99999 MMMMM 55555 .2 .2 nun n n"" e m m N m i& u n n e n wu m m ku wm mlo Hi m u a amdue H wmw & 0e. n e m 3456 33333 99999 r r HHHHH Mm a mW wunnw P v. wmm 57002 m r 02524 w 0 .3 n m" 22 PAA mdk k m mam V 15S il ll m nD m wvms m e a emm e no r a m nhm em wMmKmms mm [57] ABSTRACT A dragline boom with a pulley around which a hoist- [22] Filed: Dec. 24, 1969 [21] Appl. No.: 888,006

ing rope passes carried on its free end, mounted with the aid of bearings on a bush installed with the possibility of rotation by means of a pin on a cross-piece secured on the free end of the boom. The pin is arranged perpendicular to the cross-piece, and the longitudinal axis of this pin is ofiset upwardly relative to the longitudinal axis of the bush.

mmn 01 0 3 3 nmwn 4 ;4 7 %7 8 m H m 8 u 0 w 3 "I a "4 M 5 2 l H I I 4 m 5 u u m Wh .c m I I 0 smfm UIF mum 555 3 Clains, 2 Drawing figures DRAGLINE BOOM The present invention relates to the booms of draglines used in open-cast mining.

Known in the prior art are dragline boorm carrying pulleys on the free end of the boom around which the hoisting ropes pass; when the dragline turns, deviation of the branch of the hoisting rope carrying the bucket takes place. If the axes of rotation of the pulleys were fixed, the hoisting rope would slide with a certain force along the flanges of the pulley, and the latter would rapidly wear.

To impart mobility to the pulleys, they are mounted on a cross-piece which can rotate about the longitudinal axis of the boom, the cross-piece being installed on spherical supports or cylindrical supports and thrust bearings installed between the pulleys (see, for example, U.S.S.R. Author's Certificates Nos. l62,056, class 84d, 3/48, 1963 and 185,282, class 84d, 3/48, [964).

Because of with the considerable distance between the pulleys and, consequently, the hoisting ropes, a yoke with an equalizing pulley (which make the boom heavier) must be installed in the vicinity of the bucket, since in the absence of an equalizing pulley, considerable dynamic forces which may lead to destruction of the boom will be applied to it if one of the hoisting ropes fails.

There are also known in the art dragline booms which have on at their free end a pulley or pulleys for the hoisting ropes contained in a rocking frame resting on a fixed frame (see, for example, the instructions for the type 4250" walking dragline of the American firm Bucyrus Erie" and the type 8900" machine of the American finn Morion"). The weight of these booms is relatively great due to the provision of the fixed frame with the pulleys.

An object of the present invention is to eliminate the above disadvantages.

A main object of the present invention is to provide a dragline boom having a relatively low weight and suitable for use on draglines with one or several hoisting ropes, with a lightened free end and minimum distance between the hoisting ropes.

This object is accomplished by providing a dragline boom with a pulley on its free end installed with the possibility of turning about an axis perpendicular to its axis of rotation and with one or several hoisting ropes, which connect the bucket to a winch, passing around it, according to the invention, a pulley coaxially installed by means of bearings on a bush mounted with a possibility of rotation by means of a pin on a cross-piece secured on the free end of the boom, the pin being perpendicular to the cross-piece, while the longitudinal axis of the pin is offset upward with respect to the axis of the bush.

This makes it possible, by using a pulley with one or several grooves, to provide a dragline boom having a relatively low weight and suitable for use on draglines with one or several hoisting ropes. The use of a pulley with one groove makes it possible to avoid constructing the free end of the boom in the form of a frame, as is generally the case in single-pulley booms; the weight of the free end of the boom and, consequently, of the entire boom is reduced, and as a result the capacity of the bucket can be increased by about percent.

When a pulley with two or more grooves is used, the boom is designed without the known rocking crosspiece separating thepulley, which makes it possible to reduce the cross-piece separating the pulley, which between the hoisting ropes to a minimum. It is also possible to eliminate the yoke and the equalizing pulley for reducing the dynamic forces on the boom upon failure of a rope.

In a preferred embodiment of the boom according to the present invention, it is expedient to arrange a thrust bearing in the space between the cross-piece and the bush at the side of the bucket-carrying branch of the rope. This bearing makes it possible to transfer the force appearing upon tensioning of the hoisting ropes from the rotating bush to the fixed cross-piece and the boom.

To simplify fastening of the bearing, it is preferred to install the bearing on a pin. To limit the angle of rotation of the bush about the pin, the cross-piece is provided with inclined surfaces constituting stops against which the bush bears.

The details of the present invention will become more fully apparent from a consideration of the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an axonometric view, partly broken away and in section, of part of the boom according to the invention;

FIG. 2 is a side view of the same with parts cut out; and FIG. 3 is a general view of the dragline, showing a boom, a bucket, a winch and a rotatable frame.

A drapeline boom 1 is fixed at one end thereof to a rotatable frame 19 and a pulley 2 is rotatably attached to the opposite free end of the boom 1. and pass around pulley 2. The pulley 2 is installed by means of bearings 4 on a bush 5 coaxially with the pulley. Bearing 4 are secured on bush 5 by nuts 6 and are isolated from the ambient atmosphere by means of rings 7 with packing elements. Bush 5 is installed with the possibility of rotation about a cross-piece 8 passing through bush 5 by engag'ng a pin 9 secured on cross-piece 8 and arranged perpendicular to the longitudinal axis of the crosspiece.

The longitudinal axis of pin 9 is offset upwardly with respect to the axis of the bush.

Cross-piece 8 is rigidly attached on the free end of boom 1 in cheeks 10 with the aid of lids 11 connected to these cheeks. To prevent rotation of the cross-piece, its ends have surfaces parallel to its longitudinal axis against which abut planks l2 welded to cheeks 10. The cross-piece is so arranged that the axis of pin 9 is essentially parallel to the branch of the hoisting rope 3 which runs from the pulley 2 to the winch 18. Bush 5 is supported on the journals of pin 9 through bearings 13 installed in coaxial openings 131 in bush 5.

A thrust bearing 14 is installed on pin 9 in the space between cross-piece 8 and bush 5 at the side of the branch of the ropes 3 which carries the bucket 17. The bearing 14 is designed for resisting and transmitting the force arising when the hoisting ropes are tensioned from rotating bush 5 to fixed cross-piece 8 and boom 1.

Thrust bearing 14 is isolated from the ambient atmosphere by means of a packing ring 15 secured in bush 5 and contacting the race of the bearing.

The upper portion of cross-piece 8 has bevelled flat surfaces 16 for limiting the angle of rotation of bush 5 relative to pin 9.

When 8. bucket 17 is lifted, forces appear in hoisting ropes 3 which are transmitted from pulley 2 through bearings 4 to bush 5. The latter transmits the force through pin 9 and thrust bearing 14 to cross-piece 80 The cross-piece, in turn, transmits this force to cheeks of the free end of boom 1.

When the dragline turns, the bucket 17 submerged in the soil remains for a certain time in place, due to which hoisting ropes 3 holding the bucket deviate from a vertical plane passing through the longitudinal axis of the boom, and turn pulley 2 together with bush 5 relative to pin 9.

The angle of rotation of bush 5 is limited by surfaces 16 of cross-piece 8 against which the internal surface of bush 5 bears when it rotates relative to pin 9.

As a result of the displacement of the longitudinal axis of the pin upward with respect to the axis of bush 5, the forces appearing on the flanges of pulley 2 during the above-mentioned deviation of hoisting ropes 3 will be considerably lower than the forces that could be expected when the said axes are arranged in one plane. This makes it possible to reduce the time required for the turning of pulley 2.

it must be noted that the embodiment of the present invention described above and shown in the drawings does not exclude variation and modification of the shape and arrangement of the separate elements.

For example, the pulley 2 with two grooves described above and shown in the drawings can be replaced by two single-groove pulleys installed on a common bush 5 The pin can be replaced by journals belonging to cross-piece 8 or bush 5.

lt is understood that surfaces 16 could be arranged on bush 5.

Cross-piece 8 can be secured in cheeks 10 of boom 1 in a different way, making it possible to ensure the required position of pin 9 relative to hoisting ropes 3.

What we claim is:

l. A dragline boom fastened at one end onto the rotatable frame of a dragline and provided at its free end with cheeks disposed vertically along said boom at a predetermined distance from each other; a crosspiece extending between said cheeks perpendicular thereto and having ends rigidly secured in said cheeks; a pin rigidly fastened at the center of said cross-piece so that its axis is essentially parallel to a hoisting rope branch which runs from the free end of said boom to a winch for said dragline; a bush having two openings with a common axis and extending perpendicular to and above the axis of said bush, said bush being positioned so as to encompass said cross-piece, the ends of said pin engaging said openings in the bush; a roller contact bearing mounted on said bush in coaxial relationship therewith; a pulley for at least one hoisting rope, said pulley having a concentric opening for accomodating said roller contact bearing whereby said bearing is adapted to rotate about its axis relative to said bush and to rock together with said bus on said pin.

2. A dragline boom according to claim 1, comprising a thrust bearing mounted between said cross-piece and said bush at the side of the rope branch carrying bucket.

3. A dragline boom according to claim 2, wherein said thrust bearing is installed on said pin. 

1. A dragline boom fastened at one end onto the rotatable frame of a dragline and provided at its free end with cheeks disposed vertically along said boom at a predetermined distance from each other; a crosspiece extending between said cheeks perpendicular thereto and having ends rigidly secured in said cheeks; a pin rigidly fastened at the center of said cross-piece so that its axis is essentially parallel to a hoisting rope branch which runs from the free end of said boom to a winch for said dragline; a bush having two openings with a common axis and extending perpendicular to and above the axis of said bush, said bush being positioned so as to encompass said cross-piece, the ends of said pin engaging said openings in the bush; a roller contact bearing mounted on said bush in coaxial relationship therewith; a pulley for at least one hoisting rope, said pulley having a concentric opening for accomodating said roller contact bearing whereby said bearing is adapted to rotate about its axis relative to said bush and to rock together with said bus on said pin.
 2. A dragline boom according to claim 1, comprising a thrust bearing mounted between said cross-piece and said bush at the side of the rope branch carrying bucket.
 3. A dragline boom according to claim 2, wherein said thrust bearing is installed on said pin. 